# Lesson 8 Different Ways to Decompose

• Let’s compare different ways to subtract.

## Warm-up Number Talk: Multiples of 10

Find the value of each expression mentally.

## Activity 1 Aren’t You Missing Something?

Lin and Clare made base-ten diagrams to find the value of .

Lin

Clare

1. What do you notice about their work? What do you wonder?

2. Lin and Clare each wrote equations to show their thinking. Explain how you know which group of equations matches Lin’s work and which matches Clare’s work.

A:

B:

3. How are Lin and Clare’s methods the same? How are they different?

## Problem 1

Andre found the value of . He made a base-ten diagram and wrote equations to show his thinking.

Do you think Andre’s method is more like Clare’s or Lin’s method? Explain.

## Problem 2

Find the value of each difference. Show your thinking.

## Problem 1

Here is how Clare found the value of .

Here is how Han found the value of .

How are Han’s and Clare’s calculations the same?

How are they different?